Journal of Volcanology and Geothermal Research最新文献

{"title":"The fate of an extremely phenocryst-rich magma in producing small sub-Plinian plumes during the 17th and 30th April 2024 eruption of Mt. Ruang (North Sulawesi, Indonesia): The role of clast density","authors":"Indranova Suhendro ,&nbsp;Geri Agroli ,&nbsp;Gabriela Nogo Retnaningtyas Bunga Naen ,&nbsp;Muhammad Andriansyah Gurusinga ,&nbsp;Dini Nurfiani ,&nbsp;Friska Putri Ayunda ,&nbsp;Robinsar Jogi Yoshua Manullang ,&nbsp;Noriyoshi Tsuchiya","doi":"10.1016/j.jvolgeores.2025.108332","DOIUrl":"10.1016/j.jvolgeores.2025.108332","url":null,"abstract":"<div><div>After ∼22 years of dormancy, two vigorous sub-Plinian eruptions occurred at Mt. Ruang (North Sulawesi, Indonesia) on April 17th and 30th 2024, with an observed plume height of 9–12 and 19 km, respectively. Petrography and whole-rock XRF analysis reveal that Ruang pumices are extremely rich in phenocrysts (0.36–0.87 <span><math><msub><mi>ф</mi><mi>PC</mi></msub></math></span>; plagioclase&gt;amphibole&gt;pyroxenes&gt;olivine&gt;oxides) and dense (1.31–2.33 g/cm³), with SiO₂ contents of 54.0–56.3 wt%. This suggests that the eruption was sourced by an extremely crystal-rich basaltic-andesite magma reservoir. The magma likely received substantial recharge from the deeper-hotter source as evidenced by the prevalence of amphibole megacryst, crystal clots, and disequilibrium phenocryst textures (i.e., reverse zoning, oscillatory zoning, and fine sieves). Ash from the 17th and 30th April 2024 eruptions are classified as very fine ash (median of 29 and 26 μm, respectively) and exhibit a blocky characteristic (0.75–0.99 convexity and 0.71–0.98 solidity). This evidence, coupled with the presence of stepped surface and hackle marks textures strongly suggests the involvement of external water during the eruption. The fact that Ruang pumices are characterized by high matrix-vesicle and feldspar microlite number density values (log ∼15 m⁻³) suggests that the magma decompression was rapid, reaching 0.05–27 MPa/s. However, despite this condition, the eruption was only able to generate relatively small sub-Plinian plumes. By consulting with the huge dataset from other previous studies, we found that plume height shows a negative correlation with phenocryst content and bulk density, with Ruang pumices having the highest phenocryst content and bulk density variations. This suggests that; besides magma decompression rates and magma-water interaction, the pre-eruptive crystallinity condition within the magma reservoir is essential for controlling the plume height and hence might be used as a proxy to predict the intensity of future eruptions.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108332"},"PeriodicalIF":2.4,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Complex principal component analysis of volcanic earthquakes at Azuma volcano, Japan, recorded by a distributed acoustic sensing system (DAS) for the hypocenter determination","authors":"Takeshi Nishimura ,&nbsp;Fumiya Morisaku ,&nbsp;Kentaro Emoto ,&nbsp;Hisashi Nakahara ,&nbsp;Mare Yamamoto ,&nbsp;Satoshi Miura","doi":"10.1016/j.jvolgeores.2025.108343","DOIUrl":"10.1016/j.jvolgeores.2025.108343","url":null,"abstract":"<div><div>Distributed Acoustic Sensing System (DAS) can record ground motions with a measurement interval of a few to ten meters for a long-distance range of a few tens of kilometers. The sensor, which is a fiber-optic cable embedded underground, is protected from damage caused by lightning or pyroclastic materials. These features are useful for the seismic observation of active volcanoes. We analyzed DAS data recorded at the Azuma volcano, Japan, to determine the location of volcanic earthquakes and evaluate their reliability. Using the benefits of highly dense measurement points along the fiber optic cable, we applied complex principal component analysis (CPCA) to measure the arrival time differences of seismic waves from volcanic earthquakes. We used a relative hypocenter determination technique to accurately determine the source locations of the volcanic earthquakes recorded during our observation period in July 2019. We observed 148 small volcanic earthquakes and succeeded in determining 31 events with sufficient arrival time difference data. The obtained source locations were distributed around Jododaira, extending in the north-south direction with a length of approximately 2 km. These regions are consistent with the hypocenters determined from standard hypocenter determination using the arrival times of the P- and S-waves of volcanic earthquakes from 2017 to 2022. We also determine the source locations by using the arrival time difference measured by the cross-spectral method, which is often used in seismic wave analyses, and the number of located events is small and the obtained source locations are scattered. These results suggest that CPCA is useful for extracting signals from noisy raw seismic data and accurately measuring the arrival time difference for the source locations.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108343"},"PeriodicalIF":2.4,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of the crustal reservoir feeding La Palma 2021 eruption. Insights from phase equilibrium experiments and petrologically derived time scales","authors":"J. Andújar ,&nbsp;B. Scaillet ,&nbsp;D. Frascerra ,&nbsp;I. Di Carlo ,&nbsp;R. Casillas ,&nbsp;E.D. Suárez ,&nbsp;I. Domínguez-Cerdeña ,&nbsp;S. Meletlidis ,&nbsp;C. López ,&nbsp;A. Slodczyk ,&nbsp;J. Martí ,&nbsp;E. Núñez-Guerrero","doi":"10.1016/j.jvolgeores.2025.108327","DOIUrl":"10.1016/j.jvolgeores.2025.108327","url":null,"abstract":"<div><div>Crystallization experiments were performed on three representative samples of the 2021 La Palma eruption at variable temperatures (920–1150 °C), pressures (100–400 MPa), and H₂O-CO₂ ratios in order to shed light on the pre-eruptive reservoir architecture and evolution. Experimental data reveal that La Palma crustal reservoir was at 300 MPa (10 km), at a temperature of 1065 °C with a melt water content of 2–3 wt%, lying in the stability field of amphibole. Mineral compositional zoning along with experimental constraints and whole rock data, show that a cold magma body (850–950 °C), likely a remnant of previous eruptive episodes at La Palma, was rejuvenated by hotter magmas that increased the temperature of the bottom portion of the reservoir up to 1135 °C. Time scales derived from olivine diffusion profiles show that such a reactivation started 10–15 years prior to eruption, and was marked by at least four different injections from a deep mantle reservoir at ≥25 km. This sequence is corroborated by geophysical signals and changes of surficial fluid geochemistry monitored during that period. Olivine zoning further indicates that the last mafic recharge prior to eruption onset occurred in mid-October 2018, and was followed by a post-injection cooling phase which continued up to the date of the eruption, during which the top portion of the rejuvenated body re-entered the stability field of amphibole. This cooling period preceding the eruption could in part explain the absence of pre-eruptive seismic signals at ∼10 km, as revealed by the revision of the precursory seismic catalogue since 2017. Once initiated, the eruption drained the 300 MPa body, which in turn activated the deep-seated mantle reservoir, lying at &gt;500–600 MPa, which supplied fresh, hotter and volatile-rich magma, that was emitted during the second half of the eruptive episode. Amphibole breakdown documented in first emitted magmas is related to decompression and not to overheating of the resident magmas. The fact that the rocks emitted during the first half of the eruption do not bear textural or compositional evidence for a mafic recharge occurring a short time prior the eruption suggest that the eruption triggering is linked to the internal evolution of the reservoir (volatile build-up) or to external factors.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108327"},"PeriodicalIF":2.4,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The 70 ka ‘Perote Pumice’ inter-caldera dacite-rhyolite Plinian eruption of Los Humeros Volcanic Complex, Mexico: Lithostratigraphy, hazards, and eruption dynamics","authors":"Rafael Torres-Orozco ,&nbsp;José Luis Arce ,&nbsp;Gerardo Carrasco-Núñez ,&nbsp;Ricardo Tlalpachito-Palomino","doi":"10.1016/j.jvolgeores.2025.108340","DOIUrl":"10.1016/j.jvolgeores.2025.108340","url":null,"abstract":"<div><div>Volcanic calderas span diverse eruptive styles, magnitudes, and intensities, comprising effusive/explosive activity often wrapped in between catastrophic caldera-forming episodes. During the inter-caldera stages, frequent Plinian eruptions, fueled by chemically varied magmas, pose significant hazards. The basaltic-rhyolitic Los Humeros Volcanic Complex (LHVC), Mexico's widest active caldera system, typifies such dynamics. The 70 ka Perote Pumice (PP), the largest eruption during LHVC's inter-caldera period (164–69 ka), marks a critical phase of high-intensity volcanic activity following the main caldera-collapse (164 ka). Here, we integrate lithostratigraphic mapping (52 locations) with geochemical and microtextural analyses to reconstruct the PP eruption source parameters, hazards, and dynamics. Our findings indicate that the PP deposits, comprising 13 layers (8 fallout and 5 pyroclastic density currents) reflect progression from dacite unsteady plumes and outgassed lava-plug bursts to a sustained gas-rich rhyolite-driven Plinian column, culminating in column-collapse due to waning gas and magma supply. This catastrophic VEI-6 eruption produced 30–40 km-high columns, 4.73 ± 0.18 km³ DRE, and maximum 9 × 10⁸ ± 0.9 kg s⁻¹, depositing pumice from proximal (∼1360 km²) to distal offshore areas (max. 200 km from the source to the Gulf of Mexico). The geochemical and microtextural data suggest that both dacite and rhyolite magmas mingled, were rapidly decompressed, and fragmented, yielding pervasive banded pumice. The refined stratigraphy, eruption parameters, and dynamics underscore PP as a benchmark for high-intensity inter-caldera volcanism. Considering LHVC's potential for future silicic activity, a PP-scale event would threaten two-million people within 140 km east and southeast of the caldera.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108340"},"PeriodicalIF":2.4,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The link between geothermal resources and subsurface geological structures in the magma-rich Ethiopian rift: A case study of the Boku geothermal prospect","authors":"Habtamu Wuletawu ,&nbsp;Abera Alemu ,&nbsp;Wubamlak Nigussie ,&nbsp;Kevin Mickus ,&nbsp;Derek Keir ,&nbsp;Simeneh Wassihun ,&nbsp;Shimelis Wendwesen","doi":"10.1016/j.jvolgeores.2025.108333","DOIUrl":"10.1016/j.jvolgeores.2025.108333","url":null,"abstract":"<div><div>In the volcanically and tectonically active zones of the main Ethiopian Rift, geothermal resources are primarily influenced by subsurface geological structures along the rift valley floor which contains multiple volcanic complexes. However, the specific subsurface structures of these volcanic systems and their relation to the distribution of shallow geothermal resources remain inadequately understood. This study utilizes gravity data from the Global Gravity Model Plus2013 and ground magnetic data to investigate the role of subsurface volcanic features in the occurrence of geothermal resources within the Boku Geothermal Prospect (BGP). Interpretation of gravity and magnetic anomalies, along with derivative maps, suggests the presence of a potential geothermal heat source beneath the Boku geothermal area. The 2D joint gravity and magnetic models, combined with gravity and magnetic anomalies, indicate a dense mafic intrusion at approximately 4.5 km depth beneath the BGP, which is likely the heat source for the geothermal system. Linear features (trending NNE-SSW and NE-SW), interpreted as faults and weak zones from derivative maps, appear to play a crucial role in hydrothermal circulation by acting as conduits for transporting hydrothermal fluids, facilitated by these faults and weak zones. Our 2D models reveal interactions between Quaternary faults within the Wonji Fault Belt (WFB) and the subsurface mafic intrusion, elucidating the mechanism by which thermal heat is transported to the shallow subsurface and surface. The surface thermal manifestations are strongly correlated with the structures detected by Horizontal Derivative and Analytic Signal analyses, indicating that the BGP area is structurally controlled. This complex faulting system provides extensive permeability and favorable conditions for the occurrence of geothermal resources within the BGP.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108333"},"PeriodicalIF":2.4,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Linking monitoring data and timescales of mafic recharge during the 2013–17 eruption at Volcán de Colima, Mexico” [Journal Volcanology and Geothermal Research 460 (2025) 108285]","authors":"Gerallt E. Hughes ,&nbsp;Chiara Maria Petrone ,&nbsp;Hilary Downes ,&nbsp;Nick R. Varley ,&nbsp;Dulce Vargas-Bracamontes ,&nbsp;Raul Arámbula-Mendoza ,&nbsp;Edgar A. Cortes-Calderon ,&nbsp;Yannick Buret","doi":"10.1016/j.jvolgeores.2025.108321","DOIUrl":"10.1016/j.jvolgeores.2025.108321","url":null,"abstract":"","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"462 ","pages":"Article 108321"},"PeriodicalIF":2.4,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Age-clustered eruptive activity at La Palma (Canary Islands) during the last 4000 years: Evidence from paleomagnetic dating","authors":"Andrea Magli ,&nbsp;Paola Del Carlo ,&nbsp;Alessio Di Roberto ,&nbsp;Guido Giordano ,&nbsp;Stavros Meletlidis ,&nbsp;Massimo Pompilio ,&nbsp;Fabio Speranza","doi":"10.1016/j.jvolgeores.2025.108328","DOIUrl":"10.1016/j.jvolgeores.2025.108328","url":null,"abstract":"<div><div>The detailed knowledge of timing and dynamics of pre-historic eruptions is pivotal for volcanic hazard assessment. This is most relevant for inhabited lower slopes of active basaltic volcanoes such as La Palma (Canary Islands), where the 2021 Tajogaite eruption caused severe destruction. We paleomagnetically investigated eight La Palma Holocene eruptions which are currently loosely constrained either by few radiometric (K/Ar and ¹⁴C) ages, or by stratigraphic/archaeological evidence. The paleomagnetic directions gathered from 28 sites (300 oriented cores) were compared with updated reference models of the paleo-secular variation of the geomagnetic field direction during the Holocene. Overlapping paleomagnetic directions from the Fuego and La Fajana lava flows, along with geologic and geochemical evidence, imply that the two flows were emplaced during the same eruptive event falling within the 2000–1730 BC time window. Single paleomagnetic age windows - consistent with and narrower than available ¹⁴C age intervals - were obtained for the Malforada–Nambroque, Montaña Quemada, and Fuego–La Fajana lava flows. Conversely, the Martín, Birigoyo–La Barquita, and La Caldereta flows yielded multiple age solutions. Moreover, our data show that the flanks of the pre-historic San Antonio scoria cone are almost totally covered by pyroclastic products of the nearby AD 1677 Fuencaliente eruption. The updated chronologic framework of the pre-historic volcanic activity at La Palma demonstrates that the past four kyr are characterized by an early period with low-frequency eruptions (three lava flow eruptions between ca. 2000 BC and 300 BC), followed by a ca. 1000 yr-long quiescence period, and by a subsequent clustering of nine events during the last 1100 yr (about one eruption per century).</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"462 ","pages":"Article 108328"},"PeriodicalIF":2.4,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying precursors and tracking pulses of magma ascent in multidisciplinary data during the 2018–2023 phreatomagmatic eruption at Semisopochnoi Island, Alaska","authors":"John J. Lyons ,&nbsp;Darren Tan ,&nbsp;Mario Angarita ,&nbsp;Matthew W. Loewen ,&nbsp;Taryn Lopez ,&nbsp;Ronni Grapenthin ,&nbsp;Alicia J. Hotovec-Ellis ,&nbsp;David Fee ,&nbsp;Matthew M. Haney","doi":"10.1016/j.jvolgeores.2025.108329","DOIUrl":"10.1016/j.jvolgeores.2025.108329","url":null,"abstract":"<div><div>The 2018–2023 phreatomagmatic eruptions at Semisopochnoi Island, Alaska produced abundant long-period (LP) seismicity, harmonic and broadband tremor, and explosion signals over several well-monitored periods of eruption and quiescence. The corresponding dataset provides an excellent opportunity to investigate precursory and <em>syn</em>-eruptive geophysical signals of long-lived phreatomagmatic eruptions using multiparameter observations. We generated explosion and LP event catalogs through novel implementations of the REDPy (<span><span>Hotovec-Ellis, 2024</span></span>) repeating event detector in mid-2021 following a network upgrade and the onset of a new phase of the eruption. The hundreds of detected explosions show a high degree of infrasound waveform similarity over more than a year, indicating a repeating source mechanism likely associated with explosive magma-water interaction. The seismic LP catalog shows that events began over a month prior to renewed explosive activity at the beginning of August 2021, and that lower frequency index (FI) LPs were generated in the week prior to the onset of explosions. We applied a recently developed machine learning tool (VOISS-Net, <span><span>Tan et al., 2024</span></span>) to catalog abundant broadband and harmonic seismic tremor recorded before and during the renewed explosive activity, along with LPs and explosions. The tremor catalogs complement the LP and explosion catalogs by filling out the seismic sequence with the dominant signal types. Together, these catalogs reveal a seismic sequence of renewed unrest that started with several weeks of LP events, followed by LPs with lower FI values and harmonic tremor in the days prior to explosive activity, and finally the onset of discrete explosions and broadband eruption tremor. We interpret this sequence as the ascent of a new pulse of magma that first interacted with the hydrothermal/groundwater system to produce LPs, followed by harmonic tremor, and that ultimately drove explosive magma-water interactions and periods of continuous ash emissions. The 2021 seismic sequence, in combination with long-term records of satellite SO₂ emissions, deformation from interferometric synthetic aperture radar (InSAR) analysis, ash sample analysis, infrasound, and volcano tectonic seismicity, allows us to interpret the entire 9-year period of unrest and eruption that began with an intrusion and earthquake swarm in 2014.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108329"},"PeriodicalIF":2.4,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geothermal gas geochemistry in Southeast Tibetan Plateau margin influenced by magma chambers and fractures","authors":"Jia-Yi Wu ,&nbsp;Hai Gang Cao ,&nbsp;Peng Cheng Zhao ,&nbsp;Yu Ping Guo ,&nbsp;Xue-Gang Chen ,&nbsp;Xiaohu Li ,&nbsp;Jui-Fen Tsai ,&nbsp;Pei-Ling Wang ,&nbsp;Li-Hung Lin","doi":"10.1016/j.jvolgeores.2025.108323","DOIUrl":"10.1016/j.jvolgeores.2025.108323","url":null,"abstract":"<div><div>Hydrothermal gases play a pivotal role in elucidating the cycling of deep materials and subsurface processes. Here, we analyzed the chemical and isotopic compositions of 40 gas samples and compiled geochemical data on &gt;280 samples discharged from the Tengchong hydrothermal field, located on the Southeast Tibetan Plateau margin. Helium isotopes span from 0.13 <em>R</em>_<em>a</em> (the ³He/⁴He ratio of air) to 5.91 <em>R</em>_<em>a</em>, indicating a mixing between mantle-derived helium and crustal components. Spatial distributions of helium isotopes are closely associated with the locations of magma chambers beneath the Tengchong field. N₂/Ar ratios and nitrogen isotopic compositions suggest that N₂ and Ar were primarily contributed by atmospheric sources and groundwater, with minor N₂ contributions from mantle-derived materials. CO₂ was mostly originated from the thermal decomposition of limestone and magma degassing, with a few samples affected by secondary processes like carbonate precipitation. The chemical and carbon‑hydrogen isotopic compositions of alkanes indicate that methane was mainly sourced from thermogenic processes. The central magma chamber and its adjacent faults are characterized by the most intensive magmatic activity and the closest connection to deep materials. A gas migration and diffusion model using a crustal ³He endmember of 6 × 10⁻⁹–9 × 10⁻⁸ (volume ratio of ³He to total gases) well explains the decreasing ³He concentrations with the distance from magma chambers. Hence, the highly penetrable helium in quiescent regions like Tengchong could migrate through overlying rocks without the need of gas channeling along faults. Similarly, our model can also explain the relationships between Ar concentrations and the distance from springs to faults and magma chambers. In contrast, the geochemical characteristics of other gas components (e.g., CO₂, N₂) are closely associated with the location of major faults. This study offers valuable insights into the spatial relationships between gas geochemistry and subsurface magmatism and fault distribution, highlighting the influence of hydrothermal processes on diverse patterns of gas migration and source in hydrothermal fields.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"462 ","pages":"Article 108323"},"PeriodicalIF":2.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclical dome formation and destruction leading to highly explosive PDCs at the Late Pleistocene Tlaloc volcano, Mexico","authors":"Mario Emmanuel Boijseauneau-López ,&nbsp;Giovanni Sosa-Ceballos ,&nbsp;Xavier Bolós ,&nbsp;José Luis Macías","doi":"10.1016/j.jvolgeores.2025.108326","DOIUrl":"10.1016/j.jvolgeores.2025.108326","url":null,"abstract":"<div><div>The age, eruptive dynamics, and magmatic processes driving the explosive eruptions of the Tlaloc stratovolcano remain poorly understood. These eruptions may reflect a cyclical phase of dome growth and destruction, as suggested by lithic content variations within the Late Pleistocene units of Tlaloc. In this study, we present stratigraphic, petrological, and compositional analyses of three major units: Xichimanla (unknown age), La Joya (between 38 and 43.5 ka), and Tlaminca (∼34 ka). These units, consisting of pyroclastic density current (PDC) deposits emplaced along the NW gullies of the volcano, capture a significant part of its explosive eruptive history during the Late Pleistocene. The Xichimanla, La Joya, and Tlaminca units represent vent-opening events initiated by dome explosions, followed by boil-over-type eruptions. A distinct compositional transition from rhyodacite to rhyolite (64.16–69.25 wt% SiO₂) is evident in the units. Textural and geochemical evidence, including banded pumice, disequilibrium textures in plagioclase, amphibole, and pyroxene, as well as the presence of xenoliths, xenocrystals and mineral relics, suggest that the explosive eruptions at Tlaloc were driven by magma mixing and crustal assimilation. The interaction between a mafic recharge magma and a resident felsic reservoir generated a hybridized melt, incorporating remobilized crystal mush parts from felsic reservoirs. These processes, along with volatile input from crustal assimilation, contributed to overpressure buildup and ultimately triggered explosive activity. Amphibole thermobarometry (100–500 MPa) from the La Joya PDC points to the presence of multiple magma reservoirs beneath Tlaloc, potentially explaining the compositional and textural variability. Moreover, the shift from effusive to explosive behavior may have been triggered by the intrusion of fresh, hot magmas into deeper reservoirs, introducing volatiles and heat that facilitated melt migration toward shallower chambers before eruption. These processes could explain the explosive eruptive dynamics of other stratovolcanoes in the Sierra Nevada of Mexico.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"462 ","pages":"Article 108326"},"PeriodicalIF":2.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}